Why Is Mixing Time Crucial To Blending Uniformity

During processing time, particularly in the tablet manufacturing process, several compounds are mixed together in a dry powder blender. Many pharmaceutical companies will have considered the idea of increasing the mixing time to a level higher than the specified time; not only would this save time, but it would also cut the cost. That said, the specified mixing time is important.

The recommended mixing time is crucial in ensuring the quality of the tablet. Increasing the mixing time will cause the de-mixing or segregation of the compounds inside the mixing blender. The segregation will result in an unequal distribution of the ingredients, making the dosage highly potent in one tablet and less in another.

So, by increasing the mixing time, the powders might be de-mixed, rather than being mixed altogether. Below are some reasons for the de-mixing:

Interaction of materials: materials might not have the proper time to mix

Size of the particle: if the ingredients are of different sizes, the batch might not blend perfectly

Material density: a difference in the weight of the materials would lead to segregation of materials that have higher density

The factors discussed above all work together during the blending process. The vibration during the process allows the smaller particles to go under the bigger ones, causing segregation of the material. If the mixing time is extended, the high-density materials will then go down to the mixer’s bottom, which will also cause the ingredients to separate based on their density.

Because different materials are blended together inside the mixer, some would interact with each other more with an increased mixing time, causing the materials to blend poorly. It is important to follow the mixing time to prevent any segregation of the different components and in turn, prevent poor tablet content.